ASME B16.20 Spiral Wound Gaskets: A Comprehensive Overview
1. What Is an ASME B16.20 Spiral Wound Gasket?
ASME B16.20 is a standard developed by the American Society of Mechanical Engineers (ASME) that governs the design, materials, dimensions, tolerances, and marking of metallic gaskets—specifically spiral wound, kammprofile, and ring joint gaskets—for use with flanges covered by ASME B16.5, B16.47, and MSS SP-44.
A spiral wound gasket consists of alternating layers of metal winding (typically stainless steel) and filler material (such as flexible graphite or PTFE) wound in a spiral shape. This design provides excellent recovery and resiliency under varying loads and temperatures. Many of these gaskets also include inner and/or outer rings made from carbon or stainless steel to help center the gasket and prevent overcompression.
2. Key Benefits
- Superior Sealing Performance: The spiral design offers high compressibility and excellent recovery, making these gaskets ideal for handling temperature and pressure fluctuations.
- High Temperature and Pressure Resistance: These gaskets are typically rated for service temperatures up to 850°F (or higher) and pressures exceeding 1,500 psi.
- Wide Media Compatibility: Whether sealing water, steam, gases, chemicals, or hydrocarbons, the filler material can be selected to meet specific chemical compatibility requirements.
- Standardized Consistency: ASME B16.20 ensures dimensional accuracy, interchangeability, and predictable performance.
- Optional Inner Rings for Enhanced Protection: An inner ring improves blowout resistance, prevents inward buckling, and shields the filler from process media.
3. Common Applications
These gaskets are widely used in:
- Petrochemical plants
- Oil and gas refineries
- Power generation (thermal, nuclear, and combined cycle)
- Pulp and paper mills
- Chemical processing facilities
- Marine and offshore platforms
- Steam systems and heat exchangers
- Pipelines and compressor stations
They are commonly installed in flange joints for pumps, valves, compressors, pressure vessels, and piping systems—especially in applications where leakage is unacceptable.
4. Troubleshooting Joint Leakage
Despite their high-performance capabilities, joint leakage may still occur if installation or operational factors are not properly addressed. Key areas to investigate include:
- Gasket Centering and Fit: Improper centering can lead to uneven load distribution. Ensure outer rings match the flange size to aid alignment.
- Torque and Bolt Load: Under-torquing or inconsistent bolt tightening are common causes of failure. Follow proper bolting patterns and torque values.
- Flange Condition: Damaged, warped, excessively rough, or corroded flanges can compromise sealing.
- Media Compatibility: Chemical attack on the filler material may cause degradation. Always verify chemical resistance.
- Thermal Cycling and Vibration: Frequent temperature swings or vibration can lead to gasket relaxation. Select materials with high recovery and consider retorquing if needed.
- Incorrect Gasket Selection: Using an unsuitable winding metal or filler reduces service life. Always choose a gasket rated for the specific application.
5. Conclusion
For demanding sealing environments, ASME B16.20 spiral wound gaskets provide a high-performance, industry-approved solution that supports operational safety, equipment reliability, and regulatory compliance. When leakage occurs, these gaskets offer a systematic framework for effective troubleshooting and resolution.